Cycle timer control apparatus for traffic signals



June 30, 1942.

W. M. JEFFERS CYCLE TIMER CONTROL APPARATUS FOR TRAFFIC SIGNALS Filed Dec. 18, 1940 INVENTOR.

Patented June 30, 1942 CYCLE TIMER CONTROL APPARATUS FOR TRAFFIC SIGNALS Walter M. Jeflers, Syracuse, N. Y., assignmto Grouse-Hinds Company, Syracuse, N. Y., a corporatlon of New York Application December 18, 1940, Serial No. 370,692

3 Claims.

The invention relates to cycle timer control apparatus for traffic signals and has as an object a control apparatus embodying a construction which is particularly economical to manufacture and operate and which includes means whereby the timer is quickly and conveniently adjustable to vary the signal periods of the cycle independently.

The invention consists' in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing which is an across the line schematic wiring diagram of the control apparatus embodying, my invention,

This control apparatus is operable to cause the traflic signals at one or more intersections to be stop signal will be simultaneously displayed to the intersecting street. In the arrangement here shown, the amber or change ll, l4 are displayed to both streets between the signal changes, 7

The signals are operated by contacts comprising part of a motor driven cam imit. The signals I0, 15 are connected to a stationary contact I6 through a conductor II. The change signals l I, I4 are connected to a stationary contact l8 through a conductor l3, and the signals I2, l3 are connected to the contact 23 through a conductor 2|. All of the signals are connected to conductor 22 extending to the common side 23 of the line. Contacts 25,426 and 21 are arranged to be moved into and out of engagement with the contacts I6, l8 and 23 respectively, these movable contacts being connected to the hot side 28 of the line through a conductor 23. The con:- tacts 25, 26 and 21 are operated by cams 3|, 3!, 32 respectively, these cams being secured to and rotatable with a cam shaft 33 driven by a motor 34 which is operable, upon energization of the coil 35, to effect rotation of the shaft 33 sufllcient to shift the signal indications from one street to the other, and to effect display of the change signals II, l4. The coil 35 is connected to the hot side 23 by a conductor 36 and to a stationarycontact 31 through conductor 33 and also to a stationary contact 33 through conductor 43.

The contact 31 is connected to the common side 23 through a movable contact 42, conductor 43. The contact 33 is connected to the common return 23 through armature 44 of relay 45 and conductor 46. The contact 42 is moved into and out of engagement with the contact 31 by a cam 41 mounted on shaft 33. The contacts 31, 42 are i normally open. The armature 44 is moved into engagement with contact 33 by energization of relay 45, and when the contacts 33, 44 are in engagement the circuit is completed through the motor coil 35. The wire 43, contacts 33, 44, wire 46, constitute a starting circuit for the motor 34, and the contacts 31, 42, wire 43 constitute a running circuit for the motor 34.

The operation of the motor 34 is controlled by a thermionic tube designated generally at 33. This tube consists of a power amplifier unit and a half wave rectifying unit in a single envelope. The filament ll of the amplifying unit and the filament 52 of the rectifying unit are connected in series directly across the line by conductors 53, 54. The cathode 55 of the amplifying unit is connected to the wire 53 by conductor 33, and the output from the plate 51 is connected to relay 45 through conductor 53, the opposite side of the relay being connected to wire through wire 53. With this arrangement, the relay 4 is energized by the plate current of the tube and the armature 44 maintained in engagement with the contact 33 thus establishing the starting circuit to the motor coil 35.

The cam 41 is provided with notches 43 complemental to the lobes on the signal circuit contact earns 30, 3|, 32, and the arrangement is such that immediately upon rotation of the shaft 33, contact 42 is moved into engagement with contact 31 thus establishing the running circuit for the motor 34, which circuit remains closed until the shaft 33 has been rotated sufficiently to change from one signal indication to the other, whereupon the contact 42 is permitted to move out of engagement with the contact 31 disrupting the motor running. circuit. During the rotation of the shaft 33, contact 63 is moved into engagement with contact I, the engagement of these contacts being substantially simultaneous with the engagement of contacts 31, 42, The movable contact is connected to the plate 32 of the rectifying element of the tube. and the contact ii is connected to the grid 63 of the amplifying unit through conductor 34.

The potential on wire 34 is applied to one side of a condenser 65 through conductor 66, the opposite side of the condenser being connected to the wire 53 through wires 31, 33. Accordingly,

line voltage is applied to the condenser and the same becomes rapidly charged at substantially line voltage, effecting a high negative potential on the grid 63 with respect to the cathode 55 I and accordingly, reducing the current output from the plate 51 to a value permitting armature II to move out of engagement with contact 38. The starting circuit to the coil 35 is thus opened previous to the disengagement of the contacts 31, 82, whereby when these latter contacts are open the shaft 33 comes to rest and the signals have been shifted from one indication to the next.

The contact 88 is actuated by a cam 18 provided with notches 1| complemental to the notches 48 in cam 41, whereby the contacts 31, 42 and 68, 6| are moved into and out of engagement in unison.

The length of the period during which each signal indication is displayed corresponds to the period the motor 38 remains at rest and, as previously explained, the motor remains at rest until the relay 45 is again energized, or until the condenser 85 has been discharged to reduce the negative potential on grid 83 sufliciently to permitthe relay 45 to be energized from the output from plate 51.

A discharge circuit is connected in shunt with the condenser 85 upon the establishment of each trafllc signal period. Contacts 15, 16 and 11 are connected to the conductor 64, and the opposite side of the condenser is connected to a plurality of branch circuits l8, I8, 80, by wire 68. The branch circuits include variable resistances indicated at 8|, 82 and 83 respectively. These adjustable resistances are in turn connected to movable contacts 84, 85 and 86 which are movable into and out of engagement with the stationary contacts l5, l8, 11. The movable contacts are actuated by cams 88,89 and 90, these cams being complemental or paired with the respective signal circuit cams 38, 3|, 32. The arrangement is such that when one signal circuit is closed, a corresponding one of the variable resistances 8|, 82, 83 is connected in shunt with the condenser 65. Accordingly, the rate at which the condenser 85 discharges depends upon the adjustment of the resistance which is connected in the shunt circuit. I I

With this arrangement; each of the resistances 8|, 82, 83 may be adiusted to provide the desired length of signal period. In the structure disclosed, the resistance 8| controls the length of the period during which the stop signal I is displayed to the north-south traflic, and the-go signal IE to the east-west traflic. The resistance 82 controls the display of the amber lights l2, l8, and the resistance 83 the period during which the green light is displayed to the north-south street and the red light to the east-west street.

It will be apparent the structure described is cult contact, a motor operable to actuate said switching mechanism step by step to eilect the successive operation of said signal circuit contacts and the respective condenser discharge contacts, a starting circuit and a running circuit for said motor, said starting circuit including a relay which, when energized, eflects closing of said circuit, an electron discharge tube having the output thereof connected to said relay and being operable to normally energize the relay, said motor nmning circuit including an additional contact oi. said switching mechanism, said contact being normally open and being closed during each actuation of said switching mechanism, a condenser, a condenser charging circuit closed upon actuation of said switching mechanism. one

' side of the condenser being connected to the particularly economical to manufacture and to control grid of said tube,and a condenser discharge circuit connected through each of said condenser discharge contacts.

2. A trafllc signal controller operable to effect display of the trafllc signals through repeated traflic cycles comprising a cam unit including a cam shaft, a plurality of signal circuit contacts -niccessively actuated into open and closed position upon rotation of the cam shaft, a condenser control contact complementalto each signal circuit contact and being opened and closed in unison with said respective signal circuit contacts, a condenser charging contact and a motor running contact, each of said latter contacts bemg normally open and being closed during at least a portion of the period during which each Jf said signal circuit contacts are closed, a motor lperable, when energized, to effect rotation of said cam shaft, a motor starting circuit including a relay which, when energized, is eflfective to close said starting circuit, an electron discharge tube a circuit connected to the output of said tube and said relay and being operable to energize the latter, a condenser connected to the grid of said tube, a charging circuit connected to said condenser through said charging contact, and a separate discharge circuit for said condenser connected through each of said control contacts.

3. A trailic signal controller operable to effect I .iisplay of the traflic signals through repeated trailic cycles comprising a cam unit including a cam shaft, a plurality of signal circuit contacts successively actuated into open and closed position upon rotation of the cam shaft, a condenser control contact, complemental to each signal circuit contact and being opened and closed in unison with said respective signal circuit contacts, a condenser charging contact and a motor running contact, each of said latter contacts being normallyopen and being closed during at least .i portion of the period during which each of said signal circuit contacts are closed, a motor operable, when energized, to effect rotation of said cam shaft, a motor starting circuit includmg a relay which, when energized, is effective to close said starting circuit, an electron discharge tube, a circuit connected to the output of said tube and said relay and'being operable to energize the same, a condenser connected to the grid of said tube, a charging circuit connected to said condenser through said charging contact, and a separate discharge circuit for said condenser connected through each of said control contacts, and each of said-discharge circuits including means adjustable to vary the rate of the discharge of said condenser.

WALTER M. JE1=FERS. 

